What's New In Pyramid 1.2
=========================
This article explains the new features in :app:`Pyramid` version 1.2 as
compared to its predecessor, :app:`Pyramid` 1.1. It also documents backwards
incompatibilities between the two versions and deprecations added to Pyramid
1.2, as well as software dependency changes and notable documentation
additions.
Major Feature Additions
-----------------------
The major feature additions in Pyramid 1.2 follow.
Debug Toolbar
~~~~~~~~~~~~~
The scaffolding packages that come with Pyramid now include a debug toolbar
component which can be used to interactively debug an application. See
:ref:`debug_toolbar` for more information.
``route_prefix`` Argument to include
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The :meth:`pyramid.config.Configurator.include` method now accepts a
``route_prefix`` argument. This argument allows you to compose URL dispatch
applications together from disparate packages. See :ref:`route_prefix` for
more information.
Tweens
~~~~~~
A :term:`tween` is used to wrap the Pyramid router's primary request handling
function. This is a feature that can be used by Pyramid framework
extensions, to provide, for example, view timing support and can provide a
convenient place to hang bookkeeping code. Tweens are is a little like
:term:`WSGI` middleware, but have access to Pyramid functionality such as
renderers and a full-featured request object.
To support this feature, a new configurator directive exists named
:meth:`pyramid.config.Configurator.add_tween`. This directive adds a
"tween".
Tweens are further described in :ref:`registering_tweens`.
A new paster command now exists: ``paster ptweens``. This command prints the
current tween configuration for an application. See the section entitled
:ref:`displaying_tweens` for more info.
Scaffolding Changes
~~~~~~~~~~~~~~~~~~~
- All scaffolds now use the ``pyramid_tm`` package rather than the
``repoze.tm2`` middleware to manage transaction management.
- The ZODB scaffold now uses the ``pyramid_zodbconn`` package rather than the
``repoze.zodbconn`` package to provide ZODB integration.
- All scaffolds now use the ``pyramid_debugtoolbar`` package rather than the
``WebError`` package to provide interactive debugging features.
- Projects created via a scaffold no longer depend on the ``WebError``
package at all; configuration in the ``production.ini`` file which used to
require its ``error_catcher`` middleware has been removed. Configuring
error catching / email sending is now the domain of the ``pyramid_exclog``
package (see http://docs.pylonsproject.org/projects/pyramid_exclog/dev/).
- All scaffolds now send the ``cache_max_age`` parameter to the
``add_static_view`` method.
Minor Feature Additions
-----------------------
- The ``[pshell]`` section in an ini configuration file now treats a
``setup`` key as a dotted name that points to a callable that is passed the
bootstrap environment. It can mutate the environment as necessary during a
``paster pshell`` session. This feature is described in
:ref:`writing_a_script`.
- A new configuration setting named ``pyramid.includes`` is now available.
It is described in :ref:`including_packages`.
- Added a :data:`pyramid.security.NO_PERMISSION_REQUIRED` constant for use in
``permission=`` statements to view configuration. This constant has a
value of the string ``__no_permission_required__``. This string value was
previously referred to in documentation; now the documentation uses the
constant.
- Added a decorator-based way to configure a response adapter:
:class:`pyramid.response.response_adapter`. This decorator has the same
use as :meth:`pyramid.config.Configurator.add_response_adapter` but it's
declarative.
- The :class:`pyramid.events.BeforeRender` event now has an attribute named
``rendering_val``. This can be used to introspect the value returned by a
view in a BeforeRender subscriber.
- The Pyramid debug logger now uses the standard logging configuration
(usually set up by Paste as part of startup). This means that output from
e.g. ``debug_notfound``, ``debug_authorization``, etc. will go to the
normal logging channels. The logger name of the debug logger will be the
package name of the *caller* of the Configurator's constructor.
- A new attribute is available on request objects: ``exc_info``. Its value
will be ``None`` until an exception is caught by the Pyramid router, after
which it will be the result of ``sys.exc_info()``.
- :class:`pyramid.testing.DummyRequest` now implements the
``add_finished_callback`` and ``add_response_callback`` methods implemented
by :class:`pyramid.request.Request`.
- New methods of the :class:`pyramid.config.Configurator` class:
:meth:`~pyramid.config.Configurator.set_authentication_policy` and
:meth:`~pyramid.config.Configurator.set_authorization_policy`. These are
meant to be consumed mostly by add-on authors who wish to offer packages
which register security policies.
- New Configurator method:
:meth:`pyramid.config.Configurator.set_root_factory`, which can set the
root factory after the Configurator has been constructed.
- Pyramid no longer eagerly commits some default configuration statements at
:term:`Configurator` construction time, which permits values passed in as
constructor arguments (e.g. ``authentication_policy`` and
``authorization_policy``) to override the same settings obtained via the
:meth:`pyramid.config.Configurator.include` method.
- Better Mako rendering exceptions; the template line which caused the error
is now shown when a Mako rendering raises an exception.
- New request methods: :meth:`~pyramid.request.Request.current_route_url`,
:meth:`~pyramid.request.Request.current_route_path`, and
:meth:`~pyramid.request.Request.static_path`.
- New functions in the :mod:`pyramid.url` module:
:func:`~pyramid.url.current_route_path` and
:func:`~pyramid.url.static_path`.
- The :meth:`pyramid.request.Request.static_url` API (and its brethren
:meth:`pyramid.request.Request.static_path`,
:func:`pyramid.url.static_url`, and :func:`pyramid.url.static_path`) now
accept an absolute filename as a "path" argument. This will generate a URL
to an asset as long as the filename is in a directory which was previously
registered as a static view. Previously, trying to generate a URL to an
asset using an absolute file path would raise a ValueError.
- The :class:`~pyramid.authentication.RemoteUserAuthenticationPolicy`,
:class:`~pyramid.authentication.AuthTktAuthenticationPolicy`, and
:class:`~pyramid.authentication.SessionAuthenticationPolicy` constructors
now accept an additional keyword argument named ``debug``. By default,
this keyword argument is ``False``. When it is ``True``, debug information
will be sent to the Pyramid debug logger (usually on stderr) when the
``authenticated_userid`` or ``effective_principals`` method is called on
any of these policies. The output produced can be useful when trying to
diagnose authentication-related problems.
- New view predicate: ``match_param``. Example: a view added via
``config.add_view(aview, match_param='action=edit')`` will be called only
when the ``request.matchdict`` has a value inside it named ``action`` with
a value of ``edit``.
- Support an ``onerror`` keyword argument to
:meth:`pyramid.config.Configurator.scan``. This argument is passed to
:meth:`venusian.Scanner.scan` to influence error behavior when an exception
is raised during scanning.
- The ``request_method`` predicate argument to
:meth:`pyramid.config.Configurator.add_view` and
:meth:`pyramid.config.Configurator.add_route` is now permitted to be a
tuple of HTTP method names. Previously it was restricted to being a string
representing a single HTTP method name.
- Undeprecated ``pyramid.traversal.find_model``,
``pyramid.traversal.model_path``, ``pyramid.traversal.model_path_tuple``,
and ``pyramid.url.model_url``, which were all deprecated in Pyramid 1.0.
There's just not much cost to keeping them around forever as aliases to
their renamed ``resource_*`` prefixed functions.
- Undeprecated ``pyramid.view.bfg_view``, which was deprecated in Pyramid
1.0. This is a low-cost alias to ``pyramid.view.view_config`` which we'll
just keep around forever.
- Route pattern replacement marker names can now begin with an underscore.
See https://github.com/Pylons/pyramid/issues/276.
Deprecations
------------
- All Pyramid-related :term:`deployment settings` (e.g. ``debug_all``,
``debug_notfound``) are now meant to be prefixed with the prefix
``pyramid.``. For example: ``debug_all`` -> ``pyramid.debug_all``. The
old non-prefixed settings will continue to work indefinitely but supplying
them may print a deprecation warning. All scaffolds and tutorials have
been changed to use prefixed settings.
- The :term:`deployment settings` dictionary now raises a deprecation warning
when you attempt to access its values via ``__getattr__`` instead of via
``__getitem__``.
Backwards Incompatibilities
---------------------------
- If a string is passed as the ``debug_logger`` parameter to a
:term:`Configurator`, that string is considered to be the name of a global
Python logger rather than a dotted name to an instance of a logger.
- The :meth:`pyramid.config.Configurator.include` method now accepts only a
single ``callable`` argument. A *sequence* of callables used to be
permitted. If you are passing more than one ``callable`` to
:meth:`pyramid.config.Configurator.include`, it will break. You now must
now instead make a separate call to the method for each callable.
- It may be necessary to more strictly order configuration route and view
statements when using an "autocommitting" :term:`Configurator`. In the
past, it was possible to add a view which named a route name before adding
a route with that name when you used an autocommitting configurator. For
example:
.. code-block:: python
config = Configurator(autocommit=True)
config.add_view('my.pkg.someview', route_name='foo')
config.add_route('foo', '/foo')
The above will raise an exception when the view attempts to add itself.
Now you must add the route before adding the view:
.. code-block:: python
config = Configurator(autocommit=True)
config.add_route('foo', '/foo')
config.add_view('my.pkg.someview', route_name='foo')
This won't effect "normal" users, only people who have legacy BFG codebases
that used an autommitting configurator and possibly tests that use the
configurator API (the configurator returned by
:func:`pyramid.testing.setUp` is an autocommitting configurator). The
right way to get around this is to use a default non-autocommitting
configurator, which does not have these directive ordering requirements:
.. code-block:: python
config = Configurator()
config.add_view('my.pkg.someview', route_name='foo')
config.add_route('foo', '/foo')
The above will work fine.
- The :meth:`pyramid.config.Configurator.add_route` directive no longer
returns a route object. This change was required to make route vs. view
configuration processing work properly.
Behavior Differences
--------------------
- An ETag header is no longer set when serving a static file. A
Last-Modified header is set instead.
- Static file serving no longer supports the ``wsgi.file_wrapper`` extension.
- Instead of returning a ``403 Forbidden`` error when a static file is served
that cannot be accessed by the Pyramid process' user due to file
permissions, an IOError (or similar) will be raised.
Documentation Enhancements
--------------------------
- Narrative and API documentation which used the ``route_url``,
``route_path``, ``resource_url``, ``static_url``, and ``current_route_url``
functions in the :mod:`pyramid.url` package have now been changed to use
eponymous methods of the request instead.
- Added a section entitled :ref:`route_prefix` to the "URL Dispatch"
narrative documentation chapter.
- Added a new module to the API docs: :mod:`pyramid.tweens`.
- Added a :ref:`registering_tweens` section to the "Hooks" narrative chapter.
- Added a :ref:`displaying_tweens` section to the "Command-Line Pyramid"
narrative chapter.
- Added documentation for :ref:`explicit_tween_config` and
:ref:`including_packages` to the "Environment Variables and ``.ini`` Files
Settings" chapter.
- Added a :ref:`logging_chapter` chapter to the narrative docs.
- All tutorials now use - The ``route_url``, ``route_path``,
``resource_url``, ``static_url``, and ``current_route_url`` methods of the
:class:`pyramid.request.Request` rather than the function variants imported
from ``pyramid.url``.
- The ZODB wiki tutorial now uses the ``pyramid_zodbconn`` package rather
than the ``repoze.zodbconn`` package to provide ZODB integration.
- Added :ref:`what_makes_pyramid_unique` to the Introduction narrative
chapter.
Dependency Changes
------------------
- Pyramid now relies on PasteScript >= 1.7.4. This version contains a
feature important for allowing flexible logging configuration.
- Pyramid now requires Venusian 1.0a1 or better to support the ``onerror``
keyword argument to :meth:`pyramid.config.Configurator.scan`.
- The ``zope.configuration`` package is no longer a dependency.